scholarly journals Comparative Tribological Study of NiTi Diffusion Coated Titanium with Pure Titanium

2021 ◽  
Author(s):  
G. Khosravi ◽  
M. Heydarzadeh Sohi ◽  
HM. Ghasemi ◽  
N. Jalalian Karazmoudeh
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Intermetallic Layer ◽  
Pure Titanium ◽  
Wear Rates ◽  
Coated Materials ◽  
Pin On Disk ◽  
Titanium Diffusion ◽  
Wear Tests ◽  
Scanning Electron

Abstract Dry tribological behaviors of commercial pure (Cp) titanium and Cp titanium diffusion coated with equiatomic NiTi intermetallic layer were studied and compared at room temperature. Wear tests were performed by a pin on disk tribometer using 52100 steel pins, under various normal loads of 10, 20, and 40 N. worn surfaces were examined by scanning electron microscope, equipped with EDS analyzer. The wear rates of the coated materials were lower than those of the Cp titanium at all loads. This was mainly attributed to the higher hardness of the NiTi intermetallic layer compared to that of the untreated titanium. Furthermore, under an applying load of 10 N, a tribological layer was formed which could protect the surface from severe wear. The results also demonstrated a lower coefficient of friction in the treated specimens compared to those of the Cp materials.

Tribological Characteristics of Copper Based Composites with Al2O3 Particles at Various Temperatures

2013 ◽  
Vol 32 (5) ◽  
pp. 437-442
Author(s):  
P. Hvizdoš ◽  
M. Besterci ◽  
P. Kulu ◽  
T. Kvačkaj
Keyword(s):  
Coefficient Of Friction ◽  
Room Temperature ◽  
Structural Characteristics ◽  
Instrumented Indentation ◽  
Wear Rates ◽  
The Coefficient Of Friction ◽  
Order Of Magnitude ◽  
Pin On Disk ◽  
Equal Channel Angular Pressure ◽  
Scanning Electron

AbstractTwo copper based composites: an experimental Cu-Al2O3 and commercial GlidCop AL-60 grade (with 1.1 wt.% Al2O3) with grains size approximately 1–2 µm were treated by Equal Channel Angular Pressure (ECAP) technique in order to induce severe plastic deformation and to reduce the grain size by about an order of magnitude. Microstructure of the as-received and ECAPed states of both systems were observed. Hardness of the experimental materials was measured by instrumented indentation. Tribological properties were studied by pin-on-disk technique in dry sliding against a steel ball at a various temperatures from room temperature up to 873 K. For all systems the coefficient of friction and specific wear rates were evaluated. Worn surfaces were studied by scanning electron microscopy and level of oxidation was measured using EDX spectrometry. It was found that between 473 K and 673 K the coefficient of friction decreased significantly. At lower temperatures the finer grained systems were more wear resistant than the as-received ones. The wear rate of all systems decreased down to zero at 673 K due to formation of hard oxide rich layers. Damage mechanisms were identified and their relationship with structural characteristics was inferred.

Observations of thick and thin sections in a field-emission SEM

1994 ◽  
Vol 52 ◽  
pp. 1018-1019
Author(s):  
W. P. Wergin ◽  
S. Roy ◽  
E. F. Erbe ◽  
C. A. Murphy ◽  
C. D. Pooley
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Chemical Fixation ◽  
Thin Sections ◽  
Transmission Electron ◽  
Conventional Transmission Electron Microscope ◽  
Scanning Electron

Larvae of the nematode, Steinernema carpocapsae Weiser strain All, were cryofixed and freezesubstituted for 3 days in acetone containing 2% osmium tetroxide according to established procedures. Following chemical fixation, the nematodes were brought to room temperature, embedded in Spurr's medium and sectioned for observation with a Hitachi S-4100 field emission scanning electron microscope that was equipped with an Oxford CT 1500 Cryotrans System. Thin sections, about 80 nm thick, similar to those generally used in conventional transmission electron microscope (TEM) studies were mounted on copper grids and stained with uranyl acetate for 30 min and lead citrate for 5 min. Sections about 2 μm thick were also mounted and stained in a similar fashion. The grids were mounted on an Oxford grid holder, inserted into the microscope and onto a cryostage that was operated at ambient temperature. Thick and thin sections of the larvae were evaluated and photographed in the SEM at different accelerating voltages. Figs. 4 and 5 have undergone contrast conversion so that the images would resemble transmitted electron micrographs obtained with a TEM.

Carbon Nanotubes Improves the Tribological Properties of Ni60/Al2O3 Coatings

2013 ◽  
Vol 785-786 ◽  
pp. 864-871
Author(s):  
Shu Xiao ◽  
Xi Yun Cheng ◽  
De Gui Ma
Keyword(s):  
Carbon Nanotubes ◽  
Tribological Properties ◽  
Microstructural Characterization ◽  
Flame Spraying ◽  
Dual Roles ◽  
Wear Rates ◽  
Transmission Electron ◽  
Pin On Disk ◽  
Wear Tests ◽  
Original Coating

Carbon nanotubes (CNTs) was introduced into Ni60/Al2O3coating by flame spraying. The effect of adding CNTs on the tribological properties of the coating was studied by varying the CNTs content as 0.0, 1.5, 3.0 and 4.5 wt% in the Ni60/Al2O3powders. The microhardness tester was used to measure the microhardness of the coating. Wear tests were performed on a pin-on-disk tribometer, to evaluate the tribological properties of the Ni60/Al2O3/CNTs coatings. Microstructural characterization was performed using scanning and transmission electron microscopy. Ni60/Al2O3/CNTs coatings revealed a lower wear rate and friction coefficient compared with the original coating, and their wear rates and friction coefficients showed a decreasing trend with increasing mass fraction of CNTs within the range from 0 to 3.0 wt% due to the effects of the reinforcement and reduced friction of CNTs. The results showed that the CNTs played dual roles in improving the tribological performance of the coating, indirectly by influencing the microstructure and mechanical properties of the coating and directly by acting as a lubricating medium.

Effect of Nitrogen Electrolytes on Al2021 Alloy by Electrolytic Plasma Processing

2013 ◽  
Vol 378 ◽  
pp. 213-219
Author(s):  
Byunh Hyun Ahn ◽  
Dong Gun Lee ◽  
Je Hyun Lee ◽  
Uk Rae Cho ◽  
Bon Heun Koo
Keyword(s):  
Room Temperature ◽  
Coating Layer ◽  
Plasma Processing ◽  
Nitrogen Supply ◽  
X Ray ◽  
Composition And Structure ◽  
Electrolytic Plasma Processing ◽  
Evolution Of Microstructure ◽  
Wear Tests ◽  
Scanning Electron

AlON-Al2O3coatings were prepared on Al2021 alloy by the electrolytic plasma processing (EPP) method. NaNO2, NaNO3and NH4NO3were chosen as nitrogen supply agents. The nitrogen inducing effect was studied by a combined composition and structure analysis of the coating layer carried out by X-ray diffractometer (XRD), scanning electron microscopy (SEM) for the specimens EPP-treated at room temperature for 15 min under a hybrid voltage of 260V DC plus 200V AC (50Hz) power. Microhardness tests and wear tests were carried out to correlate the evolution of microstructure and resulting mechanical properties.

Analysis of Intragranular Misorientation Related to Deformation in an Al-Mg-Mn Alloy

2005 ◽  
Vol 495-497 ◽  
pp. 1049-1054 ◽  
Author(s):  
Yoshimasa Takayama ◽  
Jerzy A. Szpunar ◽  
Hajime Kato
Keyword(s):  
Electron Microscope ◽  
High Temperature ◽  
Room Temperature ◽  
Electron Back Scatter Diffraction ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Stored Energy ◽  
Kernel Average Misorientation ◽  
Dislocation Glide ◽  
Scanning Electron

Intragranular misorientation reflects strain generated during deformation with dislocation glide. The SEM/EBSP (scanning electron microscope/ electron back scatter diffraction pattern) technique provides is “kernel average misorientation (KAM)” as the most appropriate quantity to evaluate the strain or the stored energy for a given point. The KAM is defined for a given point as the average misorientation of that point with all of its neighbors. In the present paper two analyses of the intragranular misorientation using the SEM/EBSP technique for a cyclic deformation at room temperature and a high temperature deformation in an Al-Mg-Mn alloy are reviewed.

Effect of Mo and Bi on Mechanical Properties of Zr-Fe-Cr Alloy at Room Temperature

2013 ◽  
Author(s):  
B. F. Luan ◽  
L. Q. Yang ◽  
T. G. Wei ◽  
K. L. Murty ◽  
C. S. Long ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Electron Microscope ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Room Temperature ◽  
Mechanical Performance ◽  
Microstructure Observation ◽  
Scanning Electron ◽  
Zr Alloy

To investigate the effects of Mo and Bi on mechanical properties of a Zr-Fe-Cr alloy at room temperature, seven Zr-Fe-Cr-Mo-Bi alloys with different compositions were designed. They were subjected to a series of rolling processes and heat treatments, and then sampled to measure mechanical properties by hardness and tensile test and to characterize microstructures by scanning electron microscope (SEM) and electron channel contrast (ECC) technique. Results indicated that among them two types of Zr-Fe-Cr-Mo-Bi alloys achieve the designed goals on mechanical properties and have the following advantages: (i) the hardness of the alloys, up to 334HV after annealing, is 40% higher than traditional Zr-4. (ii) The yield strength (YS) and ultimate tensile strength (UTS) of the alloys are 526 MP a and 889 MP a after hot rolling and annealing, markedly higher than the traditional Zr alloy. (iii) Good plasticity of the new Zr-Fe-Cr-Mo-Bi alloy is obtained with about 40% elongation, which is greatly higher than the Zr-Fe-Cr-Mo alloy thanks to the addition of Bi offsetting the disadvantage of addition Mo. Furthermore, according to observations of the microstructure observation, the reasons of the effect of the Mo and Bi elements on the mechanical performance of Zr-Fe-Cr alloy were studied and discussed.

Study of Microstructure and Mechanical Properties of Extrued Spray Forming Al-8.5Fe-1.3V-1.7Si Alloy

2013 ◽  
Vol 750-752 ◽  
pp. 671-674
Author(s):  
Rong Hua Zhang ◽  
Yong An Zhang ◽  
Bao Hong Zhu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Electron Microscope ◽  
Yield Strength ◽  
Scanning Electron Microscope ◽  
Room Temperature ◽  
Extrusion Process ◽  
Spray Forming ◽  
Microstructure And Mechanical Properties ◽  
Scanning Electron

In this paper, the Al-8.5Fe-1.3V-1.7Si alloys were fabricated by spray forming and extrusion process. The microstructure and mechanical properties of the alloy were investigated by means of metallographic, scanning electron microscope and tensile test. The results indicate that the tensile strength of the extrued alloys can reach 353MPa, the yield strength 300MPa, elongation 19.12%, at room temperature. At 250°C, the tensile strength of the extrued alloys can reach 221MPa, the yield strength 208MPa, elongation 13.33%.

Microstructures and Electrical Properties of BaTiO3 PTC Ceramics

2013 ◽  
Vol 804 ◽  
pp. 118-122 ◽  
Author(s):  
Myoung Pyo Chun ◽  
Hyo Soon Shin ◽  
Sang Il Hyun ◽  
Byung Ik Kim
Keyword(s):  
Electron Microscope ◽  
Pressure Range ◽  
Room Temperature ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Reducing Atmosphere ◽  
Microscope Images ◽  
Ptcr Effect ◽  
The Relationship ◽  
Scanning Electron

The microstructure, especially porosity, of PTC (positive temperature coefficient) thermistor based on BaTiO3 was controlled with a forming pressure. The relationship between theirPTCR properties and microstructureswas investigated with an optical and SEM (Scanning Electron Microscope) images and digital multimeter. Disk samples were fabricated by pressinguniaxially at various pressures of 100~15000kg/cm2 and sintering at 1265°C in reducing atmosphere and finally re-oxidizing at 700°C in air. The porosity of the samples decreased rapidly from 45% to 8% with increasing the forming pressure from 100 to 1000kg/cm2andbecame 4% at 15000kg/cm2with slowdecreasing of porosity in the pressure range of 1000~15000kg/cm2.With increasing the forming pressure, the resistivity jump of samplesdecreased rapidlyfrom 0.5 to 2.9 at about1000kg/cm2that corresponds tothe porosity of 15% and was saturated above this pressure. It is considered that there is a critical amount of porosity for having PTCR effect, which was about 15% in our samples. In addition, the porosity of the sample has a greater influence on the resistivity jump than on theresistivity at room temperature, which is due to the oxidation of grain boundary through a favorable channel of oxygen such as a pore.

Effects of the Fraction of PTFE and Film Thickness on Wear and Friction in an ePTFE and Epoxy Composite Solid Lubricant Coating

2005 ◽  
Author(s):  
N. L. McCook ◽  
D. L. Burris ◽  
J. R. Hanrahan ◽  
W. G. Sawyer
Keyword(s):  
Film Thickness ◽  
Epoxy Composite ◽  
Composite Films ◽  
304 Stainless Steel ◽  
Solid Lubricant Coating ◽  
Wear Rates ◽  
Wear And Friction ◽  
Pin On Disk ◽  
Composite Solid ◽  
Wear Tests

Wear tests were performed on various expanded PTFE / epoxy composite films, using a 304 stainless steel pin, in a pin on disk configuration. The density and thickness of the expanded PTFE films were varied, and the effects on friction and wear were examined. It was found that there are trends for increased wear resistance with increasing density, and increasing film thickness. Wear rates less than 10−8 mm3/Nm were calculated on some of the composite films. The film thickness range from 75–510μm and the density ranged from 0.304 to 0.904 g/cm3. The tests were run at a 5N load and 1m/s sliding speed with varying sliding distances.

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